SB 945 
.S63 J7 
:opy 1 



NITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 689 f» 

Contribution from the Bureau of Entomology ^^V^T^l^ 

L. O. HOWARD, Chief .^^^''^TU 




Washington, D. C 



PROFESSIONAL PAPER. 



July 30, 1918 



THE SOUTHERN GREEN PLANT-BUG. 

By Thos. H. Jones, 
Entomological Assistant, Truck-Crop Insect Investigations. 



Introduction 

Nature of damage 

Description of stages. 

Distribution 

Review of literature . 
Unpublished records . 
Food plants 



CONTENTS. 

Page. 



Seasonal history and habits 

Number of generations annually. 

Natural enemies 

Climate as a control factor 

Methods of artificial contr; 1 

General summary 

Literature cited 



Page. 



INTRODUCTION. 

In the extreme southern portion of the United States, particu- 
larly in those States bordering the Gulf of Mexico, a large pentatomid 
bug, Nezara viridula L., is a serious pest on cultivated plants. 
Important vegetable and truck crops are subject to injury and it is 
as an enemy of such crops that the species is considered in this 
article. The investigations upon which the article is based have 
been carried on principally at Baton Rouge, La.' 

Nezara viridula is here given the name of "the Southern green 

plant-bug." The word ''Southern" is proposed to distinguish the 

species from the closely related Nezara Jiilaris Say. "Wliile the 

latter is also a pest on cidtivated plants, and approaches viridula in 

color, its range extends farther north in the United States than does 

that of viridula. 

NATURE OF DAMAGE. 

Both adults and nymphs feed by inserting their beaks into the 
plant tissue and extracting the plant juices, minute spots marking 
the points where the beak has punctured. The growing shoots of 
plants, and especially developing fruit, are preferred as feeding 

■ 1 The writer wishes to acknowledge fee cooperation, in this investigation, of Messrs. C. E. Sipith and 
J. L. E. Lauderdale, while members of the Bureau of Entomology. The drawings of figures 4, 5, 9, 12, and 
13 and the photographs (figs. 1-3 and 6-S) have been prepared by Mr. W. M. Dovener of the Bureau of 
Entomology. 

55050°— 18— Bull. 689 1 m 

BTOno^r-r^ 



'^cK 2. 



k> 



2 BULLETIN 689, U. S. DEPARTMENT OF AGRICULTURE. 

places. Attacked shoots usually wither and are either retarded in 
their growth or, in cases of severe infestation, die. Such damage 
has been noted on Irish potato and sweet potato. 

In the case of immature fruit the tissue around the point where the 
beak has been inserted does not develop normally and these points 
sometimes become centers of callous growth. The growth of devel- 
oping fruit is retarded when injured in this manner and the fruit 
often withers and drops from the plant. Injured tomatoes, 
although small and distorted, sometimes assume a yellow color. 

During 1917 injury by the nymphs to tomatoes and beans was 
demonstrated by confining nymphs with tomato fruits and grow- 
ing beans. In the case of tomato a number of small green fruits 




Fia. 1.— Injury to tomato fruit by nymphs of the Southern green plant-bug (Nezara viridula): Injured 
fruit above, normal fruit below. Developing fruit was covered with cheesecloth sacks in which njrmphs 
were confined. Fruit bearing same number was approximately same size when inclosed in sacks. 

growing in the field were closely covered with cheesecloth. In 
some of these covers nymphs were placed while other fruit was left 
to serve as checks. Examination later showed that those fruits 
with which n}Tnphs had been confined had not developed to the 
same extent as did the check fruit. In some cases the fruits upon 
which nymphs had fed withered later and dropped from the stem. 
(See fig. 1.) 

Beans growing in flowerpots were placed under covers. Nymphs 
were confined with some, while other plants were used as checks. 
No fruit developed on those plants upon which mnnphs were allowed 

. 1. •f •. 

A^ji • .1111 






SOUTHERN GREEN PLANT-BUG. 



.to feed. Wliile the amount of fruit that developed on the check 
plants was not as great as it would have been under natural field 
conditions, the effect of the feeding of the nymphs was apparent 
when plants receiving the two treatments were compared. (See 
fig. 2.) 

During 1916 an unusual type of injury to cauliflower was reported 
from Breaux Bridge in St. Martin Parish and from Terrebonne 
Parish, La. This was apparentl}" due to the feeding of both adults 
and nymphs of the Southern green plant-bug. They were numerous 




Fig. 2. — Injury to beuns hy nymphs ol Southern green plant-bug. Beans growing in tlovverpots \ver3 
placed under wire cages. No pods developed on plants at right, with which nymphs were confined. 

at and about the point where the leaf stems are attached to the main 
stalk of the plant. The stems became discolored and the leaves 
dropped prematurely. 

DESCRIPTION OF STAGES. 

THE ADULT. 

The adult (fig. 3) when viewed from above has the characteristic 
form of the family Pentatomidge, which may be described as shield- 
shaped. The dorsal surface of the body is slightly, and the ventral 
surface strongly, convex. 

In living specimens the body as well as parts of the appendages are 
usually light green, the dorsal surface being somewhat darker than 
is the ventral surface. Exceptions to this may be found in the case 
of adults collected during the cooler months of the year. .Such indi- 
viduals are darker in color, perhaps because of the lower temperatures 



BULLETIN 689, U. S. DEPARTMENT OF AGEICULTXJEE. 




to which they are subjected, the Ught green in certain individuals. 

being replaced by 
purple. Mounted 
specimens are usually 
dull green. 

There is consider- 
able variation in size, 
the average female 
being somewhat 
larger than is the 
average male. The 
sexes are differenti- 
ated by the appear- 
ance of the last ab- 
dominal segment, es- 
pecially by the pres- 
ence of a notch in the 
margin at the pos- 
terior end of the ab- 
domen of the male 
(fig. 4.). This notch is 
not present on the fe- 
male (fig. 5). A tech- 
nical description fol- 
lows. 

Subovate, dorsal surface slightly convex, ventral surface strongly so. Color usually 
green, sometimes tinged with purple. Head somewhat prolonged, angular, tylus 
equalling cheeks. Eyes very dark red or black, ocelli 
appearing as tiny beads of amber. Antenna five-jointed; 
in comparative length the order is as follows: First, sec- 
ond, fifth, third, and fourth, the fourth being the longest. 
In green specimens the distal end of third antennal seg- 
ment, and at least the distal half of fourth and fifth, is 
dark, of a red or brown color. I.abrum dark red or brown, 
a dark line extending from the end of the labrum to dark 
tip of beak. Sides of pronotum nearly rectilinear. Three 
or five white points at base of scutellum along edge of 
pronotum. Black dot at each basal angle of scutellum. Distal end of tibia, and the 
tarsi, brownish. Small black dots along sides of abdomen at posterior tip of each seg- 
ment. In purplish specimens coloration not so apparent. 
When wings are folded, entu'e surface of body, except mem- 
branous portion of wings, roughened by numerous punc- 
tures, especially dense on dorsal surface. Osteolar canal or 
orifice short, rather broad, truncated at apex, and not ex- 
tending more than half way to lateral margin of metapleura. 
From center of base of head to tip of abdomen 10 males 
average 12.1 mm., ranging from 11 to 13.5 mm. Average 
width at shoulders 7.85 mm., ranging from 7 to 8.5 mm. 
Average length of 10 females 13.15 mm., ranging from 12 to 
15.5 mm. Average width at shoulders 8.3 mm., ranging 
Average length of head about 2 mm. 



Fig. 3.— Southern green plapt-bug ( Nezara viridula ): Adult 
about 4 diameters. 



Enlarfred 




Fig. 4.— Southern green plant- 
bug: Ventral view of tip of 
abdome:i of male. Greatly 
enlargsd. 




Fig 5. — Southern green plant- 
bug: Ventral view of tip of 
abdomen of female. Greatly- 
enlarged. 



from 7.5 to 9.5 mm. 



SOUTBtERN GREEN PLANT-BUG. 



COMPARISON WITH OTHER SPECIES OF NEZARA. 

Four species, namely, viridula L., j)ennsylvanica DeG., Tiilaris Sa}^ 
and margimta P. B., usuall}^ have been considered as belonging to the 
genus Nezara.^ Whether considered of sufficient importance to be 
a generic character, or only a spe- 
cific one, the difference in the 
shape of the orifice (osteolar canal) 
is the most satisfactory character 
for separating viridula from the 
other species. In viridvla (fig. 6) 
the orifice is short, rather broad, 
truncated at the apex, and does 
not extend more than half way 
to the lateral margin of the 
metapleura. In the other three 
species (see fig. 7) it is long 
and curved, becoming grad- 
ually evanescent, and extends 
almost to the posterior lateral angle of the mesopleura.^ 







/ 




f 


% 


7p'" 




L. 







Fig. G.— Nrzara viridula: l^ortion of ventral surface 
ofmesothorax and metathorax, showing the ori- 
fice or osteolar canal. Coxae of legs ol second 
and third pairs at right. Greatly enlarged. 



THE EGG. 

The egg (figs. 8 and 9) is cylindrical, rounded at the lower end and 
flattened on top. On the top are the short, club-shaped chorial pro- 
cesses arranged in a circle and at- 
tach^l to the egg between the cap 
and the outer edge by their smaller 
ends. Their distal ends are bent 
toward the center of the cap. The 
writer has found the number of 
chorial processes on an egg to range 
from 28 to 32. Wliitmarsh (13),^ 
in his description of the stages of 
Nezara hilaris, states that there are 
as many as 65 of these processes on 
the egg of that species. 

The surface of the egg is rough- 
ened, with traces of hexagonal mark- 
ings. A number of eggs that the 
1.24 mm. and an 




Fig. 7. — Nizara hilaris: Portion of ventral sur- 
face ofmesothorax and motathorax, sho-.ving 
the orifice or osteolar canal. Coxa; of legs of 
second and third pairs at right. Greatly en- 
larged. 



writer has measured gave an 
average diameter of 0.85 mm 



average height of 



' Some writers include viridula only imder this genus, placing the other three species under the genus 
Acrostemum of Fiebcr. 

2 Some authorities mention otlier characters by which viridula may be distinguished, but the WTiter, 
finding some of these inconstant, considers it advisable to mention only the liifference in the shape of the 
orifice. 

' Numbers in parentheses refer to "Literature cited," p. 26. 



6 



BULLETIN 689, U. S. DEPARTMENT QF AGRICULTURE. 




FlG.8.— Southern green plant-bng: Egg-cluster, viewed 
from above. Enlarged al^out 6 diameters. 



When first deposited, eggs that have been kept under observation 
were of a cream color. Later they became salmon color and just 
before hatching the crimson markings of the inclosed nymphs were 
visible through the shell, a somewhattriangular area on the head be- 
ing especially conspicuous. 

NYMPH STAGES. 

There is a marked variation in the coloration of different nymphs 
in the same period of growth and individuals vary considerably in 
coloration from day to day. The writer has observed a marked differ- 
ence in coloration of different 
individuals after the third and 
fourth molts, as indicated by 
Morrill (7) in his figures of 
nymphs in the fifth ins tar. 
There are found in the fourth 
and fifth instars both light and 
dark njmiphs, as well as others 
of intermediate coloration. In 
the case of numerous individ- 
uals that have been under ob- 
servation it has been found 
that in the fourth instar the per- 
centage of nymphs of the light 
and dark types — if such they may be called — is about the same. 
Nymphs in the filth instar belong for the most part to the light type. 
In the following descriptions the color notes should not be con- 
sidered as having too great significance. Up to and including the 
third instar these notes refer, in so far as coloration is concerned, to 
normal or average mmiphs, during the summer months. For the 
nymphs in the fourth and fifth instars two forms are 
described. One represents the darkest and the other 
the lightest form that the writer has found. 

While the writer has not had the opportunity of 
examining the nymph stages of Nezara Tiilaris, the 
species with which viridula is most likely to be con- 
fused in the United States, it is evident from Whit- 
marsh's (13) descriptions and figures, especially with 
regard to the coloration and markings on the dorsal 
surface of the adbomen, that the nymphs of Tiilaris 
and viridula are quite distinct. ' In viridula the num- 
ber and arrangement of the light-colored spots on 
the dorsal surface of the abdomen of nymphs in the second to fifth 
instars, inclusive, are very constant (although some of them are not 
apparent in the fifth instar, as they are covered by the wing pads), and 
serve to distinguish the nymphs from those of liilaris, in which these 
spots are not present. (Figs. 10 and 11.) 






Fig. 9.— Egg of South- 
ern green plant-bug, 
lateral view, show- 
ing embryo within. 
Highly magnified. 



^ SOUTHERN' GREEN PLANT-BUG. 7 

Dorsally the surface of the head and thorax of all stages is rough- 
ened by punctures and wrinkles. The surface of the abdomen is 
smoother, the punctures and wrinkles present being largely con- 
fined to areas around the glands and along the sides. Short setse are 
scattered over the surface of the body and appendages. The margins 




'^^^ 




Fig. 



10. — Southerri green plant-bug {Nczara viridula): Nymph, fifth instar; light and dark types 
Enlarged about 4 diameters. (Morrill.) 



of the thorax, which in the instars succeeding the first are serrated, 
are most prominent in the third and fourth instars. 

Immediately after molting the abdomen of the nymph is quite 
fiat dorso-ventrally but it gradually becomes thicker, until just be- 
fore the new molt it is turgid and glistening. The nymph increases 





Fig. 11. — The green plant-bug (Nezara hilaris): NjTnph, filth instar; light and dark types. Enlarged 

about 4 diameters. (Morrill.; 

in size from the beginning to the end of any instar and the length and 
width is also increased through molting. 

Especially in the last two instars there is considerable variation in 
the size of different individuals in either stage even just after or 
before molting. This, of course, would be expected from the variation 
in size of the adults. 



8 BULLETIN 689, IT. S. DEPARTMENT OF AGRICULTURE. 

In molting the skin splits down the median line of the thorax and 
at the juncture of the head and thorax on the dorsal surface. Through 
this opening the nymph gradually works its way, leaving the entire 
covering of the body behind. 

FIRST-STAGE NYMPH. 

Ovate, strongly convex above, less so Vielow. Body and appendages with short, 
scattered setse. Antennae, beak, and legs long and stout. Antenna four-jointed; first 
joint shortest, second and third of about equal length, fourth longest, largest at middle 
and approaching point at tip.' Four-jointed beak reaching beyond base of abdomen. 
Eyes prominent. Claws simple, two in number, each with pidvillus. Divisions of 
body and segments of thorax, and to less extent segments of abdomen, marked l)y 
indentations along edge. 

As the nymphs issue from the eggs they ai'e colored as follows: Eyes and' a triangular 
area on top of head, one edge extending from lower point of one eye to lower point of 
other eye, crimson; remainder of head yellowish white. Thorax and al)domen golden 
yellow except for traces of transverse crimson lines which, between thorax and ab- 
domen, form a transverse band. Antennce, beak, and legs without color, nearly trans- 
parent. 

UntU the time of the first molt, when the nymphs attain a length of about 1.6 mm. 
and a width of 1.1 mm., they become gradually darker. 

The following notes refer to their coloration just before molting: 

Dorsal surface. 

Head: Eyes deep red. Triangular area on head crimson or In'owTi. At least area 
at base light yellow. Rest of head sometimes brown or in part yellow. 

Thorax: Central portion of prothorax and mesothorax light yellow, the sides and 
rear of this area sometimes tinged with red. Sides of prothorax and mesothorax 
reddish brown or brown, with yellow sometimes present along edge. Metathorax 
reddish brown or brown. 

Abdomen: Usually darker than head and thorax. For the most part dark brown, 
sometimes almost black. White spot on. either side near base. Three glands, the 
anterior one being much narrower than the other two, reddish brown with cream- 
colored spot behind and to either side of last two. Somewhat semicircular, usually 
yellowish spot on either side of each segment, its straight edge along edge. 

• 
]\')itral surface. 

Head: Light yellow tinged with red. Antennae light yellow with last segment 
somewhat dusky at tip and with crimson areas on joints near and at junctures. Beak 
light yellow with dusky tip. 

Thorax: Light yellow tinged Avith red. Legs of same color with last segment of 
tarsi somewhat dusky. 

Ahdovien: Darker than head and thorax, haA'ing dusky tinge, especially a band 
down either side extending from edge about half way to median line, containing along 
the edge yellow semicircular spots corresponding to those found on dorsal surface. 

Sometimes the whole under surface is dusky and the coloration not as distinct as 
above indicated. 

SECOXD-STAGE NYMPH. 

Shape and relative length of segments of antennae and l:)eak much as in first stage 
Sometimes almost entirely black after molting. 

The following color notes refer to mature individuals: 

1 See Table I, giving lengths of antennal segments, p. 11. 



SOUTHERN GREEN PLANT-BUG. 9 

Dorsal surface. 

Head: Black. 

Thorax: Black ex("ept for four yellow spots usually j)resent, one near entire outer 
edge of prothorax and two, similarly located, on mesolhorax. 

Abdovien: Dark reddish. Tubercles black. Minute light spots sometimes present 
on median line. \Vhen present one is usually found between first and second and 
one between second and third tubercles. Four light areas, usually white, across 
base to form what approaches a band. Row of five light dots on either side of median 
line, the first and second very small and close together. Row of six light spots along 
either side of abdomen, the posterior one smallest and sometimes not apparent. All 
light spots are either white or light yellow, those over the central portion of the 
abdomen being usually yellow. Row of eight black semicircular spots along either 
edge of abdomen, one on a segment, their straight edges on line where dorsal and 
ventral surfaces of abdomen meet. Tip of abdomen black. 

I'ciilral sKr/ure. 

Head: Black. Antennie and beak black, except for red areas between second and 
third and third and fourth antennal joints. 

Thorax: Black except for yellow spots tha,t may be present on prothorax and meso- 
thorax, corresponding to those on doreal surface, and reddish area between coxae. 
Legs black. 

Ahdnmen Reddish with row of fi\e black spots extending from tip up median line 
and row of black spots along edge, corresponding to those on dorsal surface. Tip 
black. 

About to molt they measure approximately 3 mm. in length and 2 mm. in width, 
being widest across the abdomen. 

thiki)-.sta{;e nymph. 

Shape, coloration, and general appearance saniQ as in second instar, though black 
may sometimes be replaced by olive green. 

^^^len mature it measures about 3.6 mm. in length and 2. (J mm. in width across the 
abdomen. 

FOURTH-STACE NYMPH. 

Shape as in preceding stages. The second segment of the antenna now longest. 
In this instar occur what may be termed light and dark forms as well as individuals 
of intermediate coloration. The light and dark forms are described below. When 
mature the nymph measures approximately 6.2 mm. in length and 4.7 mm. in \ndth. 

Light forv) , dorsal surface. 

Head: Pale green with black border and black line on either side of tylus where it 
joins jugum. These lines extend to middle of base of head where they join small 
black area. Eyes black. 

Thorax: Pale green with few scattered black dots and other black marlcings. Sides 
bordered with black and with orange-colored area near edge of prothorax and one of 
same color near edge of meso thorax. 

Abdomen: Darker green than head and thorax. Darkest around glands, last two 
of which are salmon colored. Four white areas along base of abdomen nearly joined 
to form what approaches a band across base. Two small white clots on median line, one 
between first and second and one l)etween second and third glands. Row of five 
white dots on either side of median line, diverging anteriorly and converging poste- 
riorly. Row of six white dots, the posterior one much smaller than others, along 
either side of abdomen just inside conncxivum. On connexivum six black-bordered, 
salmon-colored dots. 

55050°— 18— Bull. G8'J 2 



10 BULLETIN 689, U. S. DEPARTMENT OF AGRICULTURE. 

Ventral surface.. 

Head: Pale green with yellowdsh tinge anteriorly. Sides and front bordered with 
black. First joint of antenna for most part light green, others fuscous. Labrum 
fuscous, the rest of base of beak light green. Last two segments of beak fuscous. 

Thorax: Pale green with few scattered black dots and lines. Sides bordered with 
black and with orange-colored area just inside border. Femora light green. Tibiae 
and tarsi dusky to fuscous. 

Abdomen: Pale yellowish green. Sides and posterior end bordered -w-ith black, 
with salmon-tinged band just inside border. Spiracles black. 

Dark form, dorsal surface. 

Head: Dark brown, nearly black, sometimes with jugum yellow. 

Thorax: Dark bro^vn, nearly black, except for yellow area near edge of prothorax 
and one near edge of mesothorax. 

Abdomen: Dark brown, nearly black. Last two segments lighter than others 
White markings as in light form. Color of glands same as rest of ground color. Salmou- 
colored areas along connexivum absent. 

Ventral surface. 

Head: Greenish black. Beak and antennae of same color. 

Thorax: Greenish black except for yellowish areas near edge of prothorax and 
mesothorax and light, whitish band down median line under beak. Legs greenish 
black. 

Abdomen: Light yellow tinged with red and with greenish-black border at sides 
and posterior end. Row of five greenish black spots along median line. Spiracles 
black. 

FIFTH-STAGE NYMPH. 

Shape much as in preceding stages, but development of wing pads now quite pro- 
nounced and basal portion of abdomen in part covered by them. Length, when 
mature, about 10 mm., mdth about 7 mm. 

Light form . dorsal surface. 

Head: Pale green with black border and a black area at base on either side of median 
line. Eyes for most part black. 

Thorax and tving-pads: Pale green with black border on sides and Avith few scattered 
black dots and other black markings. A narrow orange-colored band just inside black 
border, more pronounced on prothorax. 

Abdomen: Pale yellowish green with black area about rose-colored glands. Yellow- 
ish-white, rounded spots located as follows: Two small ones on median liae, one 
between first and second and one between second and third glands; row of five on 
either side, just outside median line, the third and fourth largest; row of five on either 
side near connexivum, the first sometimes covered by mng-pads. On connexivum, 
at either side of each segment, a rose-colored, black-bordered, somewhat semicircular 
area, its less curved border outward. Near posterior end of abdomen these areas not 
well defined. 

Ventral surface. 

Much as in light form of fourth -stage nymph except that band jvist inside b'ack 
border of abdomen is rose colored. 

Dark form, dorsal surface. 

Head: Juga chrome orange with black border on outside edge. Rest of head and 
eyes dark brown, nearly black. 



SOUTHEEN GEEEN PLANT-BUG. 



11 



Thorax: For most part dark brown, nearly black. Black-bordered, orange-colored 
areas, one near both outside edges of prothorax and one near outside edge of both 
primary wing-pads. Yellowish area along inside edge of both primary wing-pads. 

Abdomen: Dark brown, almost black.' At base a yellowish-white area on either 
side of median line. Other yello^vish-white spots and rose-colored areas on connexi- 
viim as in light form. 

Ventral surface. 

Head: Olive green with black markings. Beak and antennae olive green to black, 
lightest near base. 

Thorax: Olive green with black markings except for chrome-orange areas near edge 
of prothorax and mesothorax. Legs olive green near base, becoming gradually darker 
to black tarsi. 

Abdomen: Light yellow tinged with red and with black-bordered, rose-colored areas 
on connexivum corresponding to those on dorsal surface. Row of four greenish-black 
spots along median line. Spiracles black. 

COMPARATIVE LENGTHS OF ANTENNAL SEGMENTS OF NYMPHS AND ADULT. 

While the measurements given in the following table are taken 
from single individuals only, they indicate the comparative lengths 
of the segments in any one stage. It will be noted that the antenna 
of the nymph is made Up of four segments while that of the adult is 
composed of five. In this connection it may be stated that the 
writer has seen an al)normal adult with one antenna composed of 
four segments and the other of five. 

Up tO' and including the third instar the fourth segment of the 
antenna is longest. In the fourth and fifth instars the second seg- 
ment is longest, while in the case of the adult the last three segments 
are of about equal length, any one being longer than either the first 
or the second segment. 

Table I. — Lengths of segments of antennx of ni/mphs and adults of Nezara, liridula. 



Stage. 



First-instar nymph. . 
Second-instar nympli 
Third-instar nymph . 
Fourth-instar nymph 
Fifth-instar nymph. . 
Adult 



First 


Second 


Third 


Fourth 


segment. 


segment. 


segment. 


segment. 


Mm. 


Mm. 


Mm. 


Mm.. 


0.14 


0.19 


0.18 


0.37 


.15 


.40 


.33 


.,53 


.18 


.60 


.50 


.67 


.29 


1.17 


.88 


1.07 


.44 


1.71 


1.22 


1.27 


.5.3 


1.07 


1.66 


1.76 



Fifth, 
segment. 



Mm. 



DISTRIBUTION. 

Bueno (9) states that Xofim vindula is recorded ''from the whole 
of Europe except the extreme north, Asia, Africa, Mahiysia, Aus- 
tralia, New Zealand, South America, at least in the north. Central 
America, and enters into the United States at the south, being found 
in Texas and Florida. " Specimens have been seen from Cuba, Porto 
Rico, and St. Croix (U. S. Virgin Islands) in the Lesser Antilles. 



1 In individuals of this form examined by the. writer flic general color of the dorsal surface of the abdomen 
is much darker than Morrill's (7) figure would indicate. 



12 



BULLETIN 689, U. S, DEPARTMENT OF AGRICULTURE. 




Fig. 12.— Map showing distribution of the Southern green plant-bug 
lathe United States. Shaded areas indicates probable distribution. 



In the United States (fig. 12) its range covers the extreme southern 
portion, although at times it occurs outside this area. In the files of 
the Bureau of Entomology there are records of its injurious occur- 
rence in South Carolina, Georgia, Florida, Alabama, Mississippi, 

Louisiana, and Texas. 
This would indicate 
that the species is 
most numerous in the 
southern portion of 
the Cotton Belt. 

From what has 
been observed in re- 
gard to the distribu- 
tion of this species, it 
is evident that it is of 
foreign origin and , like 
many others of our 
principal pests, was 
introduced into this comitry many years ago. It is also obvious 
that it would be impossible even to hazard a conjecture as to the 
source from which it obtained a foothold in the southern United 
States. 

REVIEW OF LITERATURE. 

The species was first described as Cimcx viridulus by Linnaeus (1) 
in 1758 from specimens from India and, according to Banks (6), it 
has been described since then under several other names by various 
authors. VanDuzee (5), Banks (6), and Barber (10) have mentioned 
areas and localities where it occurs and Van Duzee (5) and Parshley 
(11) have given characters by which it can be separated from closely 
related species. 

Short notes regarding Nezara viridula were published in Insect 
Life in 1889 (2) and 1893 (3, 4). The notes published in 1893 
relate to specimens sent to Washington by correspondents in Plaque- 
mines Parish, La., and Altoona, Fla. 

In 1910 Morrill (7) included a short account of the species in Bul- 
letin 86 of the Bureau of Entomology. He mentioned the specios as 
occurring on cotton, potato, and turnip, in Florida, Louisiana, and 
Texas, and gave figures of the light and d^rk types of nymphs in the 
fifth instar. 

In 1912 Bueno (9) recorded the finding of the species in a green- 
house in Brooklyn, N. Y., and stated that he believed it to have 
been introduced from Europe or Florida, though he saw no reason 
why it could not establish itself in the latitude of Brooklyn inasmuch 
as it occurred in Germany and Russia. A short description was 
included and a number of food plants listed. 



SOUTHERN GREEN PLANT-BUG. 13 

Froggatt (12), in 1916, recorded it as injuring tomato, French bean, 
and potato in New South Wales, and stated that it had appeared in 
the neighborhood of Sydney about five years previous to that date. 

It was mentioned by Watson (14), in 1917, as an enemy of various 
crops in Florida, being treated especially as an enemy of truck and 
garden crops. Hand collecting was referred to as a satisfactory 
method of control to be practiced in the garden. 

UNPUBLISHED RECORDS. 

Among the records in the files of the Truck-Crop Insect Investi- 
gations, Bureau of Entomology, there are several notes referring to 
injury by the southern green plant-bug. Specimens were taken at 
the time the notes were made and these have been seen by the writer. 

Mr. W. R. Beattie collected specimens at Mount Pleasant, S. C, 
on September 23, 1907, from tomato and stated that "in numerous 
instances" he "found as many as 5 to 20 working on a single fruit." 
On October 24 of the same year Mr. H. M. Russell reported severe 
injury to kumquats and Satsuma oranges in a grove of 1,000 trees 
at St. Leo, Fla., the insects apparently having migrated to the grove 
from neighboring cowpeas after these had died. The owner of the 
grove estimated that because of the injury he had lost all of his Sat- 
suma fruit and 250 boxes of kumquats. The inside of the injured 
fruit was dry and pithy. 

In a note from Brownsville, Tex., dated May 25, 1909, Messrs. 
D. K. McMillan and H. O. Marsh stated that these bugs were "very 
abundant during the fall and early winter on eggplant, tomato, okra, 
cabbage, and corn." 

On October 20, 1917, Mr. M. H. Carter, of Troy, Ala., sent adults 
taken from cowpeas and wrote, "they have caused thousands of 
dollars damage in south Alabama this year by destroying the field- 
pea crop." 

Mr. H. K. Laramore wrote on November 15, 1917, sending speci- 
mens collected at Jacksonville, Tex., on turnip and rutabaga, that 
the species was very common, doing "a great deal of damage to cru- 
cifers especially" and "I am told it is out of the question for them 
to attempt to raise late cowpeas in Cherokee County." 

In the office records are included also other notes which, though 
unaccompanied by specimens, pro))ably refer to this species. Dur- 
ing November, 1911, the American Sumatra Tobacco Co., of Quincy, 
Fla., wrote regarding injury that "the loss attributable to them 
can be counted into thousands of dollars. " In the case of tobacco it 
was stated that "wherever they sting a leaf it wilts the same and the 
leaf becomes absolutely worthless. " Injury to velvet beans was also 
leferred to. 



14 BULLETIN 689, IT. S. DEPARTMENT OF AGRICULTUEE. 

Writing from Winnfield, La., on December 8, 1914, Mr. C. P. Scab 
stated that "it is this bug which attacks the hma and string bean as 
well as the cowpea. The farmers tell me it is almost impossible to 
have any kind of beans or peas on account of this bug. ' ' 

February 2, 1917, Mi-. John A. Creel wrote from Clapton, Ala., 
regarding "gree^i bugs" that ''attack peas of all varieties, velvet 
beans, peanuts, sugar cane, squash, okra, butter beans, etc.," and 
stated that ' ' they attack any kind of grain or vegetable when in the 
green stage. The vegetable or grain will, after being punctured, 
become hard and dry, and good for nothing." 

FOOD PLANTS. 

Other writers have recorded Nezara viridula as feeding on beans, 
cotton, cowpea, Gynandropsis pentapJiylla, hackberry, okra, maize, 
mulberry, orange, peas, pepper, potato, rice, sugar cane, sunflower, 
sweet potato, tomato, and turnip. We have taken it on a number 
of these plants and, in addition, on Brussels sprouts, cauliflower, 
collards, eggplant, globe artichoke, mustard, and radish. 

While little damage is recorded to some of the plants mentioned 
and while it probably does not breed on all of them, it is a quite general 
feeder, Watson (14) states that it " attacks nearly all garden plants." 
Among vegetables the writer has found that serious injury is usually 
to tomato, bean, Irish potato, sweet potato, and okra. In the late 
fall and early winter the various stages are often abundant on mustard 
and turnip. They have also been observed congregated on the re- 
maining green portions of okra plants after frost. It appears that 
legumes are favored as food plants. Farmers sometimes complain 
that the bugs greatly decrease the yield of seed of cowpeas by injuring 
the developing pods. Other writers mention the species as a pest on 
cotton and orange, and the records in the Bureau of Entomology, 
mentioned above, indicate that it feeds also on cabbage, corn, peanut, 
squash, tobacco, and velvet bean. 

SEASONAL HISTORY AND HABITS. 

HABITS OF THE ADULT. 

The adults from the last generation of nymphs, some of which 
may be found feeding at Baton Rouge until late f aU and early winter, 
often congregated on mustard and turnip, usually seek hibernating 
quarters. Rosenfeld (8) lists them among the insects taken from 
Spanish moss in Louisiana during December and January. Mr. O. W. 
Rosewall, professor of entomolog}^ at the Louisiana State University, 
has informed the writer that he has taken adults during the winter 
months under logs on batture land of the Mississippi River near 
Baton Rouge. A few, however, may be found in the field during 



SOUTHERN GREEN PLANT-BUG. 15 

mild periods of weather throughout the winter. The oversvintered 
adults mate in the spring and the writer has found eggs in the field 
at Baton Rouge as early as April 13. They have also been taken as 
late as November 8. 

In feeding the adults prefer, as do the nymphs, the growing shoots 
or developing fruit of their host plants. They are active and capable 
of strong flight. Morrill (7) has recorded their capture at night 
and mentions the fact that when an electric light was turned on at 
night in a room where adults were confined they became restless. 
This was verified by observations at Baton Rouge. 

When handled tlie adults give off a disagreeable odor. On this 
account they are sometimes spoken of as "stink-bugs." 

COPULATION. 

As has been noted by Whitmarsh (13) in the case of Nezara hilaris, 
the male and female of viridula usually remain in copulation for a 
considerable period of time, firmly attached to one another by the 
tips of their abdomens and with their heads facing in opposite direc- 
tions. Copulation is also repeated at intervals, as the results of 
observations on reared individuals given in Table II will show. 

OVIPOSITION. 

The eggs are placed close together in clusters which, when viewed 
from above, have much the appearance of pieces of capped honey- 
comb (fig. 8) . Individual eggs are attached to one another, and the 
cluster to the surface upon which it rests, by an adhesive substance 
given off by the female at the time of oviposition. In the field the 
female prefers the underside of a leaf as a location for the egg mass. 
Egg clusters deposited outside of confinement and examined by the 
writer have with one exception been made up of from 60 to 116 eggs, 
A cluster taken on November 3 contained only 36 eggs. Rearing 
records also indicate that the females sometimes deposit their eggs 
in smaller clusters, but in such instances this may have been dug to 
their having been disturbed while ovipositing. 

RECORDS OF REARED ADULTS IN CONFINEMENT. 

Several adults, reared from nymphs, were kept under observation 
in the insectary until their death, especially with the idea of obtaining 
data on the period of time elapsing between the time the females 
emerged from the last nymphal skin and the time of egg laying, 
the number of eggs laid, copulation, and length of life of males and 
females. These individuals were confined in jelly glasses containing 
moist sand, a male and a female being placed in each tumbler. Green 
tomatoes were used as food and the contents of the tumblers examined 
daily. Table II includes notes made on some of the pairs. 



16 BULLETIN 68i), U. S. DEPARTMENT OF AGRICULTUEE. 

Several females never laid eggs. One of these issued on July 22 
and lived until October 30, part of the time in company with a male. 
No eggs were found in the ovaries at death. On the other hand, 
some females that laid eggs had well-formed eggs in the ovaries at 
death. Seventy-seven eggs were found in the ovaries of the female 
of Pair L after three clusters, containing 240 eggs in all, had been 
deposited. 

While one female deposited a cluster of eggs 19 days after becoming 
adult, the .average length of this period was nearly four weeks. 



SOUTIIKRN C.HREN PLANT-BUG. 



17 



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18 



BULLETIN 689, U. S. DEPARTMENT OF AGRICULTURE. 



PERIOD OF INCUBATION OF EGGS. 

Table III gives data on eggs that were laid by females in the 
insectary, in which place the eggs were also kept until they hatched. 
Jars containing the adults and eggs were examined each morning 
and the date on which eggs were noted is taken to be the date on 
which they were deposited. Ifi a like manner the date when nymphs 
were found is taken as the date of hatching. 

The eggs composing any one cluster usually hatched at approxi- 
mately the same time. An exception to this occurred in the case of 
a cluster of eggs deposited on October 16. Nymphs issued from some 
of these on October 29, when the thermograph reached a maximum 
of 87° F. at noon. At 2 p. m.^ a '^ norther" caused a sudden drop in 
temperature, the thermograph registermg 34° F. the next morning. 
No more nymphs were observed to issue on October 30 or 31 when 
the maximum temperatures were 53° and 63° F., respectively, but 
on November 1, when the maximum temperature was 70° F., other 
eggs hatched. 

The temperatures to which the different egg clusters were exposed 
apparently governed to some extent the period of mcubation, the 
period being longer for the lower temperatures. 

Table III — Incubation periods of egg clusters of Nezara viridula.^ 



De- 
posited. 


Hatched. 


Days. 


De- 
posited. 


Hatched. 


Days. 


De- 
posited. 


Hatched. 


Days. 


July 22 
July 22 
July 30 
Aug. 9 
Aug. 13 
Aug. 13 
Aug. 14 
Aug. 14 
Aug. 15 


July 28 
July 28 
Aug. 4 
Aug. 14 
Aug. 18 
Aug. 18 
Aug. 19 
Aug. 19 
Aug. 20 


6 
6 
5 
5 
5 
5 
5 
5 
5 


Aug. 18 
Aug. 20 
Aug. 20 
Aug. 22 
Aug. 22 
Aug. 24 
Aug. 25 
Aug. 26 
Sept. 2 


Aug. 23 
Aug. 26 
Aug. 26 
Aug. 28 
Aug. 28 
Aug. 30 
Aug. 31 
Aug. 31 
Sept. 7 


5 
6 
6 
6 
6 
6 
6 
5 
5 


Sept. 4 
Sept. 5 
Sept. 6 
Sept. 6 
Sept. 6 
Sept. 18 
Sept. 27 
Oct. 16 
Oct. 18 


Sept. 9 
Sept. 10 
Sept. 12 
Sept. 12 
Sept. 11 
Sept. 25 
Oct. 6 
Oct. 29 
Nov. 9 


5 

5 

6. 

6 

5 

9 
13 
22 



1 For temperatures to which eggs were exposed see figure 13. 
HABITS OF THE NYMPHS. 

The nymph issues from the egg through a circular opening at the 
top v.^hich it makes by removing the cap or Ud. The b^o^\^lish 
T-shaped egg-burster, by means of which the cap is removed, is 
usually left m the eggshell when the nymph emerges. 

During the first instar the nymphs ordinarily cluster together, 
often on the eggshells, and apparently do no feedmg. After the 
first molt they begin to search for food and soon become scattered. 
Subsequent to the first molt, and especially durmg the later instars, 
the nymphs are active and when disturbed they often seek protection 
by moving to places out of the disturber's range of vision. They are 
found usually upon those portions of the plant on which they prefer 
to feed — -the growing shoots and more especially the developing fruit. 

1 All references to "clock time" refer to Standard Time. 



SOUTHERN GREEN PLANT-BUG, 



19 




•^ SJ^J^^i/>5>^C7 — ^i/ZP^ty^^tyA/^^ 



20 



BULLETIN 689, U. S. DEPARTMENT OF AGRICULTURE. 



When handled the nymphs give off a disagreeable odor. This 
odor is scarcely perceptible in the case of n^nnphs in the first instar 
but increases in strength in the succeeding stages. 

PERIODS OF NYMPHAL STAGES. 

Tables IV and V are introduced to show the minimum number of 
days spent by nymphs from different egg clusters in the five instars. 
Table IV refers to nymphs kept in the office and Table V to nymphs 
kept in the insectary. The nymphs issumg from a single egg cluster 
were kept together in a cloth-covered jar containing moist sand. 
Green tomatoes were used as food and proved very satisfactory. 
Fresh ones were placed in the jars at frequent intervals in order that 
the food supply might approximate that in the field. 

The jars were examined daily, and the dates given for the different 
lots are those on which the first individual from a certain egg cluster 
issued from the egg or from a subsequent nymphal instar. It is 
assumed, therefore, that the first individual to issue from an egg 
cluster was the first to become adult. 

Individuals from any one egg cluster spent about the same amount 
of time in either of the first two nymphal instars, but durmg the 
later instars the periods became less constant. Temperature condi- 
tions apparently had an important bearing over this. For instance, 
during a period of warm weather in the fall a few nymphs in a certain 
instar would molt; then the temperature would suddenly fall and 
several days of cool weather follow, no other nymphs molting until 
this period had elapsed. Periods of several days, therefore, sometimes 
occurred between the time when the first and last adults appeared. 
In the fall these periods were sometimes prolonged to 30 days. 

The periods spent by the nymphs of different egg clusters in the 
succeeding instars Avere apparently influenced by the prevailing 
temperatures; low temperatures lengthening the periods. This can 
be seen by comparing the dates given in Table V with the insectary 
temperatures shown in figure 13. 



Table IV 



-Minimum length of instars of Nezara virrdula based on records of first 

indiriduals } 



Lot. 


Hatched. 


Second 
Instar. 


Third 
instar. 


Fourth 
instar. 


Fifth 
instar. 


Adult. 


A 


July 2 
July 4 


July 5 
July 7 


July 10 
July 13 


July 20 
July 19 


July 26 
July 29 


Aug. 2 


B 


Aug. 8 








Numlier of days to complete instar. 


\ 




3 1 .1 10 
3 ! f. 6 


6 
10 


7 


B 




10 

















1 Average of maximum temperatures to which nymphs were exposed, 89° F.; average cf minimum tem- 
peratures, 80° F. 



SOUTHERI^ GREEN^ PLANT-BUG. 



21 



f 



Table V. — Minimum length of instars of Nezara viridula based on records for first 

individuals.^ 



Period spent 
in first instar. 



June 18-22. 

Ajug. 14-17. 
Aug. 18-22. 
Aug. 19-22. 



Do ... . 

Aug. 20-23. 
Aug. 23-27. 
Aug. 28-31. 



Do 

Aug. 30 to Sept 3. 
Aug. 31 to Sept. 3. 

Aug. 31 to Sept. 4. 

I 

Sept. 7-10 



Sept. 9- 13.. 
Sept. 10-14. 
Sept. 12-17. 

Oct. 6-15. .. 
Oct. 11-17. . 
Oct. 14-lS. . 



Period spent 

in second 

instar. 




June 22-26 


4 


Aug. 22-29 

Aug. 22-26 

Aug. 22-28 


4 
6 


Aug. 23-29.... 


G 


Aug. 27 to 

Sept. 2. 
Aug. 31 to 

Sept. 7. 
Sept. 3-8 


6 

7 


....do 

Sept. 4-8 

Sept. 10-19.... 


5 
4 
9 


Sept. 13-20.... 


7 


Sept. 14-20.... 


6 


Sept. 17-25.... 


8 


Oct. 17-29 


1? 


Oct.l8toNo\. 


23 


10. 





Period spent 
in third instar. 



June 26 to July 
4. 

Jnlv7-13 

July 7-12 

July 24-30 



Aug. 26 
Sept. 1. 

Aug. 28 
Sept. 4. 

Sept. 8-16. 



to 



.do. 



do 

!-'ept. 19-27.... 
Sept. 20-2S 

do 

Sept. 25 to 
Oct. 5. 



Period spent 

in fourth 

instar. 



July 4-12. 



July 12-22 

July 13-22 

July 26 to Aug. 

3." 
Julv30to.\ug. 

5. 
Sept. 1-7 



Sept. 4-11... 

Sept. 16-22.. 

Sept. 16-23.. 
Sept. 16-25.. 
Sept. 27 t 
Oct. 6. 

Sept. 28 t' 

Oct. 8. 
Sept. 28 

Oct. 9. 
Oct. 5 IS. 



to 



Period .spent 
in fifth instar. 



July 22-31... 

Aug. 3-10... 
Aug. 5-12. .. 
Sept. 7-20... 

Sept. 11-26.. 

Sept. 23 ( 

Oct. 6. 
Sept. 24 t 

Oct. 17. 
Sept. 25 t 

Oct. IS. 

Oct. 6-29 

Oct. 6-28 

Oct. 8-29.... 



Oct. 9-28. 



9 

7 
7 
13 

1.5 

13 

23 

:3 

23 

22 
21 

19 



1" 1 



' For temperatures to which nymphs were exposed see figure 13. 
NUMBER OF GENER.\TIONS ANNUALLY. 

As has been stated, eggs have been taken in the field at Baton 
Rouge as early as April 13, and as late as November 8, while njTnphs 
in the fifth instar were observed December 23. Life-history studies 
were conducted in an msectary where both the maximum and mini- 
mum temperatures are sMghtly higher than those given by the 
Weather Bureau of the United States Department of Agriculture 
for Baton Rouge (fig. 13). Under these conditions it would appear 
that, while the egg and nymphal stages may be passed in about a 
month, during the summer months, adults usually do not begin 
egg-laymg until nearly four weeks after molting the last nymphal 
skhi. Field and inscctary observations indicate that four genera- 
tions develop annually in the field at Baton Rouge. 

NATURAL ENEMIES. 

In spite of the disagreeable odor of the species of tlie genus, tlie 
Bureau of Biological Survey has recorded finding specimens of 
Nezara in the stomachs of certam birds, but it appears to have been 
always hilaris that was foimd. N. viridula is probably also eaten. 

Morrill (7) and Wliitmarsh (13) mention the fact that the eggs of 
hilaris are parasitized by a species of Trissolcus, and it would thus 
appear that the eggs of viridula would also be attacked by this para- 




22 BULLETIN 689, IT. S. DEPAETMENT OF AGRICULTURE. 

site, although many egg clusters of viridula collected in the field 
failed to show any evidence of parasitism. 

A PARASITE. 

Trichopoda pennipes Fab. — Morrill (7) mentions the presence of 
the egg of a tachinid fly on a nymph in the fifth instar collected at 
Quincy, Fla., among a lot of 39 specimens m stages susceptible to 
parasitism by tachmids. The writer has fomid tachinid eggs com- 
mon on adults taken at Baton Rouge, and in aU cases where the fhes 
have been reared they have proved to be adults of Trichopoda 

pennipes (fig. 14), which is known 
to attack a number of the larger 
Plemiptera . Upon completing 
their growth the larvae left the 
bodies of their hosts and trans- 
formed to puparia in the soil. The 
puparium is cylindrical in shape 
with rounded ends. It measures 
about 7 mm. in length and 3.5 mm. 
in widtli and when fully colored is 
(lull reddish black. 

Of 73 adults collected on mustard 

Fia. W.— Trichopoda pennipes, a tachnid fiy_^^ , /i-inii--io i ^ r- 

parasitic on the Southern green plant-bug: Uecember 6, 1915, 13 males and 5 

Adult. Enlarged about 3 diameters. (Chit- femalcS, Or liCarly 25 pCr CCUt, 

tenden.) , ' . . , '' , _ ^ , ., i 

bore tachmid eggs. Most of the 
adults had only one egg upon them, but one had two, two three, 
and one four. Of the 26 eggs on all adults, 4 were on the dorsal 
surface and 20 on the ventral surface, while 2 were on the eyes. 
Four eggs were fomid on the head, 10 on the pro thorax, 3 on the 
mesothorax, 2 on the metathorax, 5 on the abdomen, and 2 on the 
wing covers. An egg has also been observed on the femora of one 
of the fore legs. 

The surface of the egg that is quite firmly attached to the host is 
usually flat. The opposite surface is strongly convex and is ellip- 
soidal m outline. The entire surface of the egg is glistening and is 
marked by nmiute hexagonal reticulations. The egg measures 
about 0.54 mm. in length and 0.35 mm. in width. Its color varies 
from white to gray, apparently being white when first deposited. 

PREDACIOUS ENEMIES. 

Podisus 'imaculiventris Say. — A single instance of this common 
pentatomid bug preying upon Nezara viridula was noted in the field 
at Baton Rouge during December, 1914. This individual had a 
nymph in the fifth instar impaled on its beak. 

Eutliyrhynchus jioridanus L. — Among the notes in the Bureau of 
Entomology files made by the late H. M. RusseU, mention is made 
of two predacious enemies observed by him in Florida during 1907. 



SOUTHERN GREEN PLANT-BUG. 23 

Specimens of Nezara viridula accompanied the notes. At Dade 
City, on November 1 1 , an adult of the peutatomid bug EutJiyrhjnchus 
Jloridanus was found with its rostrum thrust mto a mature individual. 
Bicytes quadrlfasciata Say. — Mr. S. A. Rohwer of the Bureau of 
Entomology states that a bembecid wasp which Mr. Russell collected 
at St. Leo, Fla., October 22, 1907, belongs to this species. The 
specimen was taken while in flight with an adult of Nezara viri- 
dula grasped in its mandibles. 

CLIMATE AS A CONTROL FACTOR. 

Whitmarsh (13) considers climate an important factor in the 
natural control of the related Nezara Jiilaris in Ohio. Cold winters, 
or periods of cold weather following unusually w^arm weather during 
the winter months, killed many individuals of that insect. Observa- 
tions made in connection with Nezara viridula in the Gulf States 
indicate that sudden drops in temperature during the winter months 
kill many individuals in the field. In Florida Mr. H. M. RusseU 
found, on December 5, 1907, "a few dead adults after the freeze" of 
the preceding night. Writing from Brownsville, Tex., on May 25, 
1909, Messrs. D. K. McMillan and H. O. Marsh stated that the 
"species has been conspicuously absent for several months, though 
very abundant during the fuU and early winter * * *" and 
added "It may be that the two freezes of January 15 and early 
February ma}^ have had some influence." 

The "WTiter Jias found that in the insectary at Baton Rouge indi- 
viduals, especially in the nymphal stages, are sometimes killed by 
low temperatures during the winter months. 

METHODS OF ARTIFICIAL CONTROL. 

It is weU know^n that the pcntatomid bugs and other large plant- 
bugs are quite resistant to contact insecticides, and the experiments 
indicate that it is difficult to control the southern green plant-bug 
by using insecticides of this type. 

SPRAYING WITH NICOTINE SULPHATE. 

Individuals in various nymphal instars, as wcU as adults, have 
been drenched with dilutions of nicotine sulphate which con- 
tained 40 per cent of nicotine by weight in combination with 
yellow laundr}^ soap at the rate of 2 pounds to 50 gaUons of water. 
These individuals were then kept under observation in the insectary 
and the effects of the different mixtures upon them noted. A 
dilution of 1 part nicotine sulphate to 300 parts of water killed aU 
nymphs, but even in the proportion of 1 to 100 the nicotine had 
httle effect on the adults. A dilution of 1 to 600 was not effective 
against nymphs in the third, fourth, and fifth instars. On the 



24 BULLETIN" 689, IT. S. DEPAKTMENT OF AGEICULTURE. 

day following the treatment over 50 per cent were active, and even 
in the case of nymphs in the third instar at least 50 per cent survived. 

SPRAYING WITH KEROSENE EMULSION. 

Experiments with strong mixtures of kerosene-soap emulsion also 
gave unsatisfactory results. One part of stock solution, made up of 
kerosene and yellow laundry soap, to two parts of water did not 
kill all nymphs that were drenched with it. Undiluted kerosene, 
as would be expected, quickly killed individuals in both the nym.phal 
and adult stages. 

In the experiments it was noted that nymphs which, immediately 
after being drenched with a contact insecticide, apparently showed 
signs of approaching death, recovered later. 

HAND PICKING. 

Hand picking can be- done profitably where valuable vegetable 
crops are being attacked. The bugs may be collected in a receptacle 
containing a little water coated with a film of kerosene, or some 
other collectmg device may be used. Wliere the bugs occur on other 
than low-growing plants the receptacle may be a pan or wide- 
mouthed dish and the bugs may be brushed or knocked from the 
plants into it. Collecting can be done best in the early morning, or 
during cool weather, when the bugs are sluggish. In addition to 
collecting and destroying the adults and nymphs, the destruction of 
egg clusters is recommended. 

In order to secure a, maximum reduction in the amount of damage 
done to the plants, hand picking not only should be carefully done, 
but should be put into practice when the attack begins. 

USE OF TRAP CROPS. 

The adults are attracted to mustard and turnips during the fall, 
as indicated by the collections referred to below. These were mad3 
from a few plants in a garden at Baton Rouge where serious injury 
by the species is seldom noted. About 15 minutes a day were 
spent in the work, all collections being made from the same plants. 
It would appear that after the first collection the succeeding adults 
were individuals that came to the plants from the time of one collec- 
tion to the next, it being unlikely that many adults escaped at the 
time each collection was made. 

On October 24, 47 adults were collected; on October 25, 81; on 
October 28, 79; and on October 31, 42. In addition to the fore- 
going 249 adults, 148 nymphs were collected. 

The fact that nymphs and adults are often very abundant in the 
late fall on turnip and mustard suggests that a few of these plants, 
or others on which the southern green plant-bug is found to congre- 
gate, might be grown as trap crops in sections where serious injury 
occurs. The bugs might be hand picked or killed by spraying with a 



SOUTHERN GREEN PLANT-BUG. 25 

strong contact intectide or b}^ using a gasoline torch. Even if it 
were found necessary, in order to kill the njTnphs and adults econom- 
ically, to use measures that would injure the plants, the operation 
might prove profitable in areas where serious damage occurs. AA^ierc 
the plants have not been grown especially as trap crops the destruc- 
tion of the- nymphs and adults when they congregate in large numbers 
would assist materially in reducing their destructiveness. 

SUMMARY OF CONTROL MEASURES. 

It would seem that spraying with a contact insecticide is not prac- 
tical, unless emplo3'ed in connection with trap crops v.'here injury 
to the plants by the insecticide is not of importance. TMiile it is 
possible to use mixtures strong enough to kill even the adults, the 
injurious effects of the insecticide upon the plants, as well as their 
present cost, would have to be considered. 

The writer is inclined to agree with Watson (14) that hand pick- 
ing is the most satisfactory control measure where valuable vegetable 
crops are seriously attacked, but for less valuable crops it is question- 
able whether tliis could be profitably done. 

The fact that the adults congregate on turnip and mustard late 
in the fall in Louisiana suggests that a few of these, or other plants 
upon which they congregate, might be grown to serve as a trap crop. 

GENERAL SUMMARY. 

A pentatomid bug, Nezara viridula Jj., here given the common 
name of the southern green plant-bug, causes severe injury to culti- 
vated crops in the southern portion of the Cotton Belt of the United 
States. Among the vegetable and truck crops injured are tomato, 
beans, Irish potato, sweet potato, okra, mustard, and turnip. 

The species is widely distributed over the world and attacks a 
great variety of plants. 

The adults and nymphs cause injury by inserting their beaks into 
the plant tissue and extracting the juices. Young growing shoots 
and developing fruit are most seriously injured. 

Life-history studies have been carried on at Baton Rouge, La., in an 
insectary where the average maximum and minimum temperatures are 
slightly higher than those given by the United States Weather Bureau 
for the same locality'. One female began egg-laying 19 days after be- 
coming adult, although the average length of this period for the several 
females under observation was about four weeks. The number of 
eggs deposited by different females varied greatly. Some laid no 
eggs, while one deposited 240 and had 77 well-developed eggs in the 
ovaries at death. The eggs are placed^ in clusters, and in the field 
they have been found always on the underside of leaves. These 
clusters were made up of from 36 to 116 eggs. 



26 BULLETIN 689, U. S. DEPARTMENT OF AGEICULTXJRE. 

In the insectary the minimum period necessary for the incuba- 
tion of the eggs was 5 days. For the five nymphal stages the mini- 
mum periods were 3, 4, 5, 6, and 7 days, respectively, a total of 
30 days for the egg and njmiphal stages. The temperatures to wliich 
the eggs and nymphs were exposed apparently had a bearing on the 
length of the period of any stage. Development was more rapid 
during the summer than during the fall. 

Eggs have been found in the field at Baton Rouge as early as 
April 13 and as late as November 8. It is probable that in this 
latitude four generations may develop in a year. Adults are found 
hibernating during the winter months, but they also occur on plants 
in the field during mild periods of weather during this season. 

Four enemies have been observed, the tachinid fly Triclwpoda 
pennipes Fab. apparenth^ being the most important. 

As a method of control the collection and destruction of eggs, 
nymphs, and adults is recommended where valuable vegetable 
crops are attacked. Adults congregate on turnip and mustard 
during the faU and a few of these plants, or others on which 
they congregate, might be grown as trap crops in sections where 
serious injury by the species occurs. The adults may be collected 
from these plants and destroyed. 

LITERATURE CITED. 

(1) LiNNE, Carl von. 

1758. Systema Naturae, ed. 10, rev., v. 1. 824 p. Holmiae. • 

Page 444: Short original description of species as Cimex viridulus, in Latin. "Habitat 
in Indiis." 

(2) [Riley, Charles V., and Howard, Leland O.] 

1889. Special notes. In U. S. Dept. Agr. Div. Ent. Insect Life, v. 2, no. 3, p. Gl. 
Review of "Notes on Indian insect pests," which forms Number 1 of Volume I 6t 
"Indian Museum Notes." First part by E. T. Atkinson makes mention of occurrence 
on potato halms. 

(3) [Riley, Charles V., and Howard, Leland 0.] 

1893. Extracts from correspondence. The sweet-potato root-weeviL In U. S. 
Dept. Agr. Div. Ent. Insect Life, v. 5, no. 4, p. 261. 

Sent to Washington with larvae of Cylas formicarius with letter from correspondent 
in Plaquemines Parish, La., dated December 22, 1892. 

(4) [Riley, Charles V., and Howard, Leland 0.] 

1893. Extracts from correspondence. Plant-bugs injuring oranges in Florida. 
InV. S. Dept. Agr. Div. Ent. Insect Life, v. 5, no. 4, p. 264, 265. 

Sent in by correspondent from Altoona, ria.,with letter dated December 7, 1892. 
Puncturing rind of nearly ripe or ripe oranges on tree. 

(5) Van Duzee, Edward P. 

1904. Annotated list of the Pentatomidae recorded from America north of 
Mexico, with descriptions of some new species. In Trans. Amer. Ent. 
Soc, V. 30, p. 1-80. 

Given in table of species of Nezara (p. 57, 58). Statement that Dr. Uhler said that 
species inhabited littoral plains of United States from Virginia to Florida and Louisiana. 

(6) Banks, Nathan. 

1910. Catalogue of the Xearctic Hemiptera-Heteroptera. American Ento- 
mological Society, Philadelphia. 103+viii p. 
Page 88: Synonymy. Distribution given as Southern States. 



SOUTHERN GREEN PLANT-BUG. 27 

(7) Morrill, A. W. 

1910. Plant-bugs Injurious to Cotton Bolls. V. 8. Dept. Agr. Bur. Knt. 

Bui. 86. 110 p., 25 Jig., 5 pi. 

Pages 82-83: Observations concerning occurrence on cotton, potato, and turnip in 
Florida, Louisiana, and Texas. Mention of tachinid egg on nymph in Florida. Original 
figures of light and dark types of nymphs in fifth instar (fig. 10) . 

(8) ROSENFELD, J. H. 

1911. Insects and spiders in Spanish moss, /n Jour. Econ. Ent., v. 4, no. 4, 

p. 398-409. 

(9) BUENO, J. R. DE LA ToRRE. 

1912. Xezara viridula Linn^, an hemipteron new to the northeastern United 

States. In Ent. News, v. 2.3, no. 7, p. 316-318. 

In greenhouse in Brooklyn, N. Y., December 10, 1911. Author believes it brought 
from Europe or Florida; sees no reason why it could not establish itself about Brooklyn, 
because of occurrence in Germany and Russia. Distribution, food plants, short de- 
scription, and mention of character by which species may be separated from hilarts 
and pennsylvanka. 

(10) Barber, H. G. 

1914. Insects of Florida. II. Hemiptera. Tyi Bui. .\mer. ]\Ius. Xat. Ilist., 

V. 33, art. 31, p. 495-535. 
Page 523: Gives localities where species has been taken in Florida. 

(11) Parshley, H. M. 

1915. Systematic papers on New England Hemiptera. II. Synopsis of the 

Pentatomidae. In Psyche, v. 22, no. 5, p. 170-177, pi. IG. 
Page 175: Given in synopsis, though not known to occur in New England. 

(12) Froggatt, W. W. 

1916. The tomato and bean bug (Nezara viridula Linn.). In Agr. Gaz. X. S. 

Wales, V. 27, pt. 9, p. 649-650, 1 pi. 

First appeared on tomato plants in the neighborhood of Sydney some five years previ- 
ously. Increased in numbers during last two years and has become a pest of the fruits 
and foliage of tomato, the foliage and yoimg pods of French beans, and potato plants. 
Short account of distribution, injury, and stages. Suggests hand picking and use of 
"oil spray or tobacco and soap wash " against nymphs, as methods of control. Original 
figures of egg, first, second, and fifth instar nymphs, and adult. 

(13) Whitmarsh, R. D. 

1917. The green soldier bug, Nezara hilaris Say. Ohio Agr. Exp. Sta. Bui. 310, 

p. 517-552, 15 figs. [4-1]. 

An extended, well-illustrated account concerning the related Nezara hilaris Say, 
based principally on observations in Ohio. Information regarding food plants, life history, 
habits, parasite, and climate as a control measure. Description of stages and an account 
of character and extent of injury to peaches, as a pest of which it is considered. In 
introduction (p. 519) statement that this "or more probably a closely related species, 
Nezara viridiUa," has been reported as an enemy of peaches in Florida. 

(14) Watson, J. R. 

1917. Florida truck and garden insects. Univ. of Fla. Agr. Exp. Sta. Bui. 134, 
p. 34-127, fig. 10"-66. 

Pages 83-84: General accoimt under name of "pumpkin bug." Attacks nearly all 
garden plants, especially legumes and particularly co\\'pea. Several generations a year, 
adults hibernating in fall and coming out early in spring. Control difficult. Young 
may be killed by kerosene emulsion or strong soap solutions but adults only at strengths 
that would injure plants. Hand collecting, in morning or on cold, rainy day, practical 
in garden or in particularly valuable patch of cowpeas. In ordinary field of cowpeas 
planting plenty of seed and keeping plants growing vigorously recommended. Men- 
tioned elsewhere in bulletin as injurious to beans, okra, peas, pepper, Irish potato, 
sunflower, and tomato. 



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